In order to compensate for the loss of a middle reliever, one of the starters will be available in relief during the middle of their extended break. The exclusions to that possible role are Mark Buehrle and Gavin Floyd.

The six-man rotation will give the starters some relief since the Sox embark on a stretch of playing on 20 consecutive days without a scheduled day off starting Friday, and Guillen wants to ensure the health of Buehrle and Floyd through the entire season.

Manager Ozzie Guillen said he sees no reason not to stay with a six-man rotation if it works past the 20-day experimentation period that began with Phil Humber’s start against the Athletics on Friday night.

“If we like what we see, of course we’ll keep it at six,’’ Guillen said when asked if he can envision it in place deep into the summer. “Yes. Because I don’t see no reason to change it.’’

Santos wasn’t used Sunday the way a closer would normally be handled. When on the road in extra innings, teams typically save closers in case they take the lead and need to shut down the victory in the bottom of the inning. …

“[If I did,] all of a sudden, I have to stick with him,” Guillen said. “All of a sudden you don’t see him in the ninth and it’s, ‘What happened here? You said he was going to be the closer.’ When you are there, close the game. I think it’s too early to say this is the guy we are going to use. We’re not save that many games. But every time he’s there, he does the job. I hope he just wait a little bit for what’s going on and then we do something or tell him.”

Humber credited Cooper with helping him add a slider to his repertoire during spring training.

‘‘[Before] I was fastball, curve, change,’’ Humber said. ‘‘The slider takes a lot of pressure off my other breaking ball because it gives hitters something else to think about.’’

Humber has been using his slider early in counts and throwing the curve as his put-away pitch.

and

Right-hander Jesse Crain tinkered with a split-fingered grip on his changeup last year in Minnesota, refined it in spring training and has mastered it this season.

The pitch looks like a fastball, then sinks late.

‘‘It’s been good, something else to keeps hitters off balance,’’ said Crain, who also throws a good curve and plus-fastball. ‘‘It’s slower [around 83 mph], it kind of fades into a righty and fades away from a lefty. Got some jams from righties and swings and misses and rollovers from lefties.’’